Apparatus and method for spinning fibers in precipitating baths



Aug. 11, 1931.

A. P. FURMAN 1,818,549 APPARATUS AND METHOD FOR SPINNING FIBERS INPRECIPITATING BATHS Filed March 21 1929 IN VEN TOR all Patented Aug. 11,1931 UNITED STATES r ATE NT orrici:

ABRAHAM I. FURMAN, OF NEW LONDON, CONNECTICUT, ASSIGNOR TD THAMES SILKCOMPANY, OF NEW LONDON, CONNECTICUT, .A CORPORATION OF ECONNECTICLUTAPPARATUS AND METHOD FOR SPINNING FIBERS IN PREGIPITATING BAT-HSApplication filed. March 21,1929. Serial No. 348381.

This invention relates to apparatus and methods for spinning fibers in aprecipitating bath and has particularly to do with the initial startingor spinning of fibers. Silk, for example may be dissolved in a solutionand then precipitated by ejecting the same under pressure from aspinneret into a bath containing an agent capable of precipitating thesame. In silk spinning operations considerable difficulty has beenexperienced in starting the same and also some difficulty, though to alesser extent, has been experienced in the subsequent clogging of thespinning devices. The herein described method and apparatus has beenevolved in an effort to eliminate such troubles and defects and has beensuccessful in practical spinning operations.

In the drawings:

Fig. 1 is an elevation showin the essential parts of the apparatus in pace including a container for the precipitating bath (the latter shownin vertical cross-section) Fig. 2 is a crosssectional view illustratinga filter with certain parts in elevation; and

Fig. 3 is a cross-sectional view of a spinneret and cap therefor.

Referring to the drawings, particularly to Fig. 1, 2 designates a tankwhich may be made of any suitable material containing a precipitatingbath; 4C a pipe leading from a supply of the fibroin solution or othermaterial to be precipitated under pressure; 6 designates a gear pumpwhich may be connected to a suitable source of power (not shown); and 8a by-pass with its valve 10 around the pump 6. The pump 6 is connectedby means of a pipe 12 to the filter 14, which filter (see Fig. 2) mayinclude alternate layers of suitable woven wire and textile fabric so asto remove from the liquid all traces of foreign matter or solidparticles of suflicient size to interfere with the spinning operation.The filter 14 is connected by means of a pipe 16 to the spinneret head,generally designated at 20. The spinneret head also preferably includesan additional filter which may be made up of alternate layers of wovenwire and textile of the liquid under "the :hi

fabricso that the material. to be precipitated I A 'is filteredat the'last possible moment before it is .actually ejected from the spinneretinto the bath through the holes 22 Ein'lthe :sp'inneret plate 24, whichplate is suitably held by means of :the screw threaded fermile member'26. There Ei-s shown in 'Figs. (l and .3 a 'cap :28 applied to thespinneret head :and connected by a cord 30 to the .top iott the jar 2 soas to be readily available; The cap 28 may b610,fl111bb81-010lill61suitable material adapted to form a tight joint with the ferrule '26.

The herein described apparatus is zillustrative of apparatus that may beemployed :to practice the herein described methods, though it will be:understood that the specific and preferred form "of apparatus may bealtered :to practice such method by aequiara- :lent means.

In practice :I :prefer to supply the fihroin solution or :material to bespun at a considerable head of pressure in the pipe 4 and simply employthe gear pump 61182 [metersing device to regulate the normal :flow aotfthe liquid from :the spinneret. ln starting the spinning operation withthe apparatus as shown, I first place the cap'r28 over the spinnerethead and immerse the same with its :pipe filled with :air in theprecipitating bath, then the valve 10 :isopened in the pass 8 round thepump so that theliiu ll )fOBCB plied :by means not show n3, for example40 or :pounds, is allowed to rush around :the

h :pressume (supmeterrngzpumpGa-nd into the line 'l2athereb'y V:rapid'ly building up a considerable *fluid :(liquid or pressure in the=line to the spinneret head 20. This pressure itends to .lift or removethe cap :28, though if :necessary its removal may be vaidetl by ;agentle tug on the cord 30 so that the spinneret holes 22 are kept {freeand clear of the precipitating bath by what may :be termed the pilotfluid, until the fibroin solution :following, itself fills the :holes.Upon the fibroin solution :passing through the holes into the rbathit isat once continuously :precipitated rand Ehardened iinto :fila'inent formandirises to the t'op :oflthe-zbath wvherezit anay v be gathered andreeled. It will be apparent that the pressure need only be sufiicient toprevent the entrance of the precipitating bath into the holes 22, but Iprefer to use the suggested pressure in order to prevent any chance ofthe holes being clogged so as to interfere with the passage of theliquid. But should there be any tendency for the precipitating liquid toenter it is at once blown clear of the holes by reason of the higherpressure of the fluid issuing from the spinneret. Upon the spinningoperation being well started, the speed of the pump may be regulated soas to provide the proper rate of flow for the desired spinning speed andthe by-pass valve 10 is then shut off so that the normal spinningoperation may be carried on. Though I prefer to start the spinningoperation by means of the by-pass device as described it will be clearthat a similar result may be obtained by a temporary speeding up of thepump 6 so as to provide a relatively high rate of flow of the fluid orair preceding the liquid to be precipitated.

Having described and explained my preferred form of apparatus, theprinciple thereof, and the best mode in which I have contemplatedapplying that principle, I claim:

1. The steps in the process of spinning fibers in a precipitating bathwhich consists in immersing a spinneret in said bath, maintaining theholes in the immersed spinneret clear of said precipitating bath, andthen passing the liquid to be precipitated through said spinneretwhereby to initiate in said bath the formation of attenuated fibers.

2. The steps in the process of spinning fibers in a precipitating bathwhich consists in immersing a covered spinneret in said bath,maintaining the holes in the immersed spinneret clear of saidprecipitating bath, and then passing the liquid to be precipitatedthrough said spinneret whereby to initiate in said bath the formation ofattenuated fibers.

3. The herein described method of starting a fiber spinning operation ina precipitating bath which'consists in passing a fluid rapidly throughthe holes in a spinneret and into said precipitating bath thuspreventing the entrance of the bath into said holes, then causing thematerial to be precipitated to pass rapidly through said holes wherebythe spinning operation is initiated and fibers formed, and then spinningsaid fibers through said holes at a regulated speed suitable for anormal spinning operation.

4. An apparatus for spinning fibers is a precipitating bath having aspinneret, means for covering said spinneret head while immersed in aprecipitating bath, means for passing a fluid through the holes

